This invention relates to height finding arrangements for radar systems of the type using a mechanically rotated planar antenna array for range and azimuth determination.
A typical range/azimuth radar surveillance system uses a mechanically rotated planar antenna array in conjunction with a pulsed transmitter and receiving system to provide range and azimuth data for targets within a prescribed coverage volume. Many such radars will, in addition, be able to discriminate among plural targets in any given range/azimuth cell by virtue of their different relative velocities (and hence different Doppler shifts) in the direction of the radar. In the prior art, such capability is most commonly achieved by `linking` the receiver local oscillator(s) coherently with the transmitted frequency and applying a succession of received signals to "Doppler filters", each filter responding to a different Doppler frequency shift.
Prior art systems have not provided accurate and economically instrumented height-finding in a continuously scanning mode. The manner in which the present invention advances this art will be understood as this description proceeds.